Gear-grinding machine



March 25, 1930. J QTT'ET AL I GEAR GRINDING MACHINE Filed July 27, 1925 s Shets-Sheet 1 March 25, 1930. A, J, QTT ET AL 1,751,753

GEAR GRINDING MACHINE Comm L012 Match 25, 1930. A. J. QTT ET AL 1,751,753

GEAR GRINDI NG MACHINE Filed July 27, 1925 8 Sheds-Sheet 5 5% IIIIIIIIIIIIIlIIIIHI/IIIIIIIIIIIIIlllfiiiifiiiiiii]IlI/IMIMI/I/I/I/I/II/I/I/n A. J. OTT ET AL GEAR GRINDING MACHINE Filed July 27, 1925 8 Sheets-Sheet 4 lDT March 25, 1930.

March 25, 1930. J OTT ET AL GEAR GRINDING MACHINE Filed July 2'7, 1925 8'Sheets-Sheet 5 8 Sheets-Sheet 6 March 25, 19309 n ET AL GEAR GRINDING MACHINE Filed July27, 192s March 25,1930. A. J. on ET AL 1,751,753

GEAR GRINDING MACHINE Filed July 27, 1925 8 Shee csSheet 7 lvwemtow GHQ: men-:- I

' March 25, 1930. J, OTT ET AL GEAR GRINDING MACHINE Filed Jul 27, 1925 8 Sheets-Sheet 8 Patented Mar. 25, 1930 UNITED STATES PATENT ,oFFicE.

ALBERT J. OTT AND CONRAD L. CTT, OI DETROIT, MICHIGAN, ASSIGNOBS TO AMERICAN GRINDER COMPANY, OF DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN GEAR-GRINDING MACHINE Application filed Jul 27,1925. Serial No. 48,885.

The invention relates to an improved gear grinding machine of the generating type 1n which the gear is given a rollin motion relative to the grinding wheel by t e simultane- 5 ous reciprocation and oscillation of the work carrying spindle. In general construction, our improved machine is similar to that described in our copending application Serial Number 615,583, filed January 29, 1923, which may be referred to for the underlying principles of generation. This'application is directed primarily to certain improved features of construction which enhance the utility of the machine. provedmachme looking toward the front and One of the objects of the invent-ion is to r g t side thereof; provide a mechanism for adjusting the angu- Flgure 2 1s a fragmentary sectional front larity of the grinding wheel spindle relative elevatlon Ishowmg the grinding wheel head to the gear to be ground in order that both d splndle; sides of the gear teeth may be generated without reversing the gear upon the work; spindle. This feature is particularly advantageous when grinding stem gears and certain cluster gears for with this class of work it is often inconvenient and sometimes impossible to reverse the gear end for end in a grinding machine.

Another object is to provide means for adjusting the travel of the reciprocating carriage to adapt the same for various sizes of gears. Our improved travel adjustment regulates both the length of the stroke and also the position of the work spindle with respect to the grinding wheel. p

A further object is to provide a grinding 0f h m e; machine in which the wheel guard is mount g ye 9 18 11 elevatien of a portion of the ed independently of the grinding wheel sping de 9f the machine showing portions dle and arranged to permit accessibility so of h ge 111869131011; that the wheel may be removed from its spin- F g 10 1S a on 0n 311611116 10 0f dle without disturbing the guard. Our imgl proved construction also permits the angular g fi 1S ag tary rear View iladjustment of the wheel spindle to grind lustlfatmg h fi fi f e 0f the tapes; either side of the gear teeth without corre- F g 12 1S 3 gmm atlc front view sponding adjustment of the wheel guard. showing the reversal of the grinding wheel;

A still further objectisthe provision of an automatic stop mechanism whereby either the carriage alone may be stopped after the com- I pletion ofv a predetermined number of gear teeth or both the carriage and the grinding wheel may be simultaneously stopped. The to automatic stopping of both the grinding wheel and the work spindle is particularly desired upon the completion of the teeth of the ground gear and replace an unground gear whlle the grinding wheel is stationary.

Another object is the provision 0 an imrelation to the grinding wheel.

Still further objects reside in other features 'of construction which are hereinafter more fully set forth. I

In the drawings Figure 1 is a perspective view of the im- 3-3 of Figure 2; 1

the machine;

Figure 5 is a fragmentary side elevation showing the work spindle in section;

Figure 6 is a sectional plan view of the carriage bed with the-'carria e partly removed, this view also showing ,t e automatic stop mechanism in sectional plan; 1

Figure 7 is a vertical section view looking so from the rear of the machine and illustrating the automatic stop mechanism;

ing wheel in position to grind the back side of the gear teeth; the dotted lines showing normal position; Figure 14 is a perspective view showing the adjustment of the carriage travel.

,In general, our machine comprises a base gear becauseitis preferable to remove the proved means for locating the work in proper V Figure 3 is a transverse section on the line Figure 4 is an elevation of the left side of the driving mechanism for the carriage and Figure 13 illustrates in full lines the grind- Figure 8 is a rear view of the lower portion A, on which a carriage B is longitudinally reciprocable. The carriage has transversely journaled therein a work spindle C adapted to receive the gear to be ground D at one end thereof and provided at the opposite end with a tape drum E. Flexible tapes F are wrapped around the drum E to extend in opposite di- 1 rections and are anchored upon an adjustable tape carriage G, the latter being carried by ways I-I upon the base A. Between the tape drum E and the forward end of the work spindle C is an automatic indexing mechanism I adapted to index the gear D one tooth after each reciprocation of the carriage. The indexing mechanism forms no part of the present invention, but is fully described in our copending application, Serial Number 31,152 filed May 8, 1925. A rotatable grind is provided with the vertical ways 15 on which is vertically slidable the wheel carriage 16, the vertical adjustment being obtained by the adjusting screw 17 which engages a nut 18 attached to the carriage by the bracket 19. Swivelled on the carirage 16 is a swivel head 20 comprising an annular housing 21 and the projecting hub portions 22. The wheel spindle 23 is journaled in suitable bearings 24 in the hub portions 22 I and extends outward beyond the same for receiving the grinding wheel hub 25. Keyed to the spindle within the housing 21 is a driving pulley 26 through which rotation is imparted to the spindle 23 by a suitable belt drive (not shown). The pulley 26 is arranged between the vertical ways 15 of the base so that the belt drive may extend therebetween into engagement with the driving mechanism hereinafter more fully described.

In order to provide for the angular adjustment of the swivel head 20 an annular adj usting ring 27 is arranged between the swivel head and the carriage 16 and is firmly secured to the latter by means of bolts-28. The swivel head 20 is also secured to the ring oybolts 31 having heads 32 engaging an annular slot 30. Thus, when the bolts 31 are all tightened, the swivel head is positively secured to the carriage. The ring 27 has a portion of its outer periphery provided with gear teeth 33 and these teeth are engaged by a pinion 34 mounted on a shaft 35 extending parallel to the axis of the swivel head. The shaft 35 is journaled in a bearing 36 in a projecting portion 37 of the housing 21 and carries at its opposite end a worm wheel 38adapted to mesh with a worm 39 upon a vertical shaft 40, the latter being also journaled in the projecting portion of the housing. The upper end of the shaft 40 projects through the housing and is provided with a squared portion 41 which may be engaged by a suitable handle (not shown).

The grinding wheel 42 is attachable to the hub 25 by means of the annular clamp 43 and the clamping bolts 44. The wheel is conical at its outer periphery as indicated at 45 and has the grinding face 46 in a plane perpendicular to the spindle 23. In order to true the grinding surface 46 We have provided a truing mechanism arranged in a housing 47, the latter attached to the swivel head 20 by the'bracket arm 48 and secured thereto by bolts 49. A shaft 50 is journaled in the housing 47 parallel to the spindle 23 and carries at its outer end a swinging arm 51 provided with a diamond truing point 52. The arm 51 is adapted to be fed slowly across the face of the grindihg wheel by means of a hand wheel 53 secured to a shaft 54 and connected to the shaft 50 by a reduction gearing. This gearing comprises a worm 55 upon the shaft 54 meshing with a worm wheel 56 upon a cross shaft 57, the latter carrying also a worm 58 adapted to mesh with the worm wheel 59 upon the shaft 50. Thus, by rotating the hand wheel 53 at a moderate speed, the diamond point 52 is moved very slowly across the grinding surface 46 resulting in a very accurate surface.

In order to provide for the wearing of the grinding surface, the wheel spindle 23 may be adjusted longitudinally in the swivel head 20 and as shown, this adjustment is accomplished as follows. The end of the spindle 23 opposite the grinding wheel carries a thrust collar 60 having the thrust bearings 61 and 62 mounted upon opposite sides thereof. 63 is a thrust housing having the inwardly projecting flanges 64 and 65 engageable with the respective thrust bearings. This housing is secured to a feed screw 66 having peripheral threads 67 engageable with the feed nut 68. A thrust flange 69 on the feed nut enga es the shoulders 70 upon the feed housing 71, the latter being secured to the hubs 22 of the swivel head by the bolts 72. The feed nut 68 has secured thereto by-the bolts 73 a feed gear 74 having peripheral teeth 75. 76 is a hand wheel rotatably mounted upon the said housing 71 and having pivotally mounted thereon the feed pawl 77 normally held in engagement with the teeth 75 bya spring pressed plunger 78 bearing against the upper arm 79 of the pawl. With the construction as above described, the longitudinal adj ustment'of the grinding wheel may be effected by rotation of the hand wheel 76 thereby moving the wheel spindle 23 within the swivel head 20.

The normal position of the grinding wheel is illustrated by the full lines in Figure 12 clined an amount corresponding to the piessure angle of the tooth to be ground. en in this position the carriage 16 is at the 11' per end of the vertical ways 15 and the w eel spindle 23 points downwardly. When it is desired to grind the opposite side of the gear teeth without reversing the gear end for end, the grindin wheel is arranged in the position shown in dotted-lines in Figure 12. In order to effect this adjustment the carriage 16 is lowered on the vertical ways 15 and the swivel head 20 is adjusted to incline the wheel spindle upwardly so that the plane of the grinding wheel assumes an inclination in the opposite direction equal to the pressure angle of the gear. The grinding wheel is removed from the hub 25 by loosening reversed and replaced upon t e hub with the grinding face on the opposite slde. For angularly adjusting the swivel head 20 the bolts 31 are first loosened and the rotat1on of the housing 21 effected by rotating the shaft 40. Since the pinion 34 is in mesh with the gear teeth 33 upon the ring 27 and since th1s ring is secured to the carriage 16 the turning of the shaft will rotatablyadjust the housing 21 to the degree desired. Figure 13 illustrates the engagement of the grindlng wheel with the gear tooth, the full lines indicat ng the wheel in aposition to grlnd the coast s1de of the tooth and the dotted lines indicating the wheel in position for grinding the driving'side of the tooth. It should be noted that the plane of the grinding face corresponds with the sides of an imaginary rack adapted to mesh with the gear.

It is the usual practice to provide grinding wheels with a wheel guard mounted upon the wheel spindle and surrounding the wheel itself. Such a construction is undesirable in our grinding machine because it would require that thewheel guard be removed each time the wheel were reversed for grindlng the opposite sides of the gear teeth. We have therefore, provided a different construction in which the wheel guard is mounted upon the base of the machine and is of suificient size to permit the angular adjustment of the grinding wheel within the same without adjustment of the housing. Thus, as shown n Figures 1 and 4, the base A is provided with an upwardly extending front houslng and at the left side witha side plate 81. The latter has hingedly connected thereto by the hinges 82 a door 83 of sufiicient size to psimit removal of the grinding wheel from the v housing when the door is swung outwardly.

The top of the door has hingedly connected thereto a water guard 84, Wl'llClLflS shown,

is closed upon the top, front and left sides.

- The water guard is arranged to enclose the space adjacent the gear while the grinding is taking place, but is adapted tobe swung back upon the hinges 85 to remove the gear. For

- retaining the water guard in any position of the clamp 43,

adjustment, the following construction is used. A collar 86 is secured to one of the hlnges 85 and is provided with teeth 87. A slmllar collar 88 1s keyed to the pivot rod 89 and has corresponding teeth 90 engageable With said first-mentioned teeth. A sprm 91 is sleeved u on the rod 89 between the co lar 88 and an a utment 92. The arrangement is such that the water guard is normally held 1n adjusted position by the engagement of the teeth, but upon manual adjustment by means of the handle 93 relative movement of the collars 86 and 88 is permitted. With the housing construction as above described, it

will be apparent that the door 83 and water that angular ad'ustment of the wheel is permitted, indepen ently of the housing.

Our machine is driven from a horizontal shaft 94 at the rear of the machine through the pulley 95 which may be connected to an outside power source. A clutch 96 connects the wheel pulley 95 to the shaft 94 and is operated by a shifting fork 97. 98 is the driving pulley for the grinder wheel and is in alignment with the pulley 26 upon the spindle 23 and is connected thereto by a suitable belt (not shown). 99 is a carriage drive pulley adapted to be connected to a driven pul ley 100 upon a countershaft 101 arranged beneath the carriage B. A clutch collar 102 is longitudinally movable upon the shaft by means of a shifting arm 103 and carries the clutch teeth 104 adapted to engage correspondin clutch teeth 105 on the pulley 100. The sha 101 is connected to the cam drum shaft 106 by suitable reduction gearing which as shown, comprises the pinion 107, idler gear 108, idler pinion 109 and drive shaft gear 110. The cam drum shaft 106 is arranged beneath the carriage bed 111 and has secured thereto, the drum cam 112, the latter bein provided with a cam slot 113 in which a ro ler 114is inserted. The roller is carried b a pin 115 depending from an oscillating l e of the machine. The arrangement is such that upon rotation of the cam drum 112 the lever 116 is given an oscillatory motion. A block 118 is longitudinally slidablein a slot 119 in the lever and has a pin 120 projecting upwardly therefrom and engaging a transverse slot 121 in a cross member 122. The latter is adapted to be clamped to the carriage B b means of the clamping strips 123 and the olts 124. For securing the'pin 120 to the cross member .122, the upper end. is threaded at 125 for receivinga clamping nut 126. Thus, by loosening the nut the block 118 may be adjusted toward or away from the pivot 117 of the lever 119 and in this manner the stroke of the carriage may be varied.

It is also desirable to provide for a longi- I ver 116 pivoted at 117 to the bed lines to that shown in dotted lines, the worktudinal adjustment of the carriage B relative to the grinder wheel in order to com pensate for the change in horizontal location of the grinder wheel when mounted for grinding the opposite sides of the gear teeth. Thus as clearly illustrated in Figure 12, when the angular adjustment of the grinder wheel 42 is effected from the position shown in full ing portion of the grinder wheel is displaced horizontally and a corresponding adjustment of the normal position of the carriage is required so that the gear may be brought into new postion. This adjustment may be accomplished by removing the bolts 124 from the carriage B, thereby disengaging the cross member 122 from the carriage. The carriage is then moved horizontally on the ways 111 for the required distance and at the same time the adjustable tape carriage G is correspondingly moved on the ways H. The carriage B is then again secured to the cross member 122 by means of the clamping strips 123 and the bolts 124, the latter being inserted in the apertures 124*, which are provided in the proper location on the carriage B. The tape carriage G is also secured in adjusted position to the ways H by means of suitable clamping means which, as shown, comprises the clamping bolt G.

As before stated one of the objects of our invention is to provide an automatic stop mechanism which will stop either the car riage alone or the carriage and the grinding wheel. For accomplishing this result, we have provided the following mechanism.

' Rising upwardly from the base A is a housthe spring pressed plunger 136.

ing 128 for the automatic stop mechanism which supports a horizontal shaft 129. A ratchet wheel 130 is journaled upon the shaft 129 and a ratchet lever 130 also rotatably mounted on said shaft carries a lateral arm 131 projecting into the path of the carriage B. The end of the arm 131 is provided with a finger 132 having an inclined face 133. adapted to be engaged by the actuating memher 134 on the carriage.

The ratchet lever 130 has pivotally mounted thereon a ratchet pawl 135 held in enga ement with the teeth of the ratchet wheel y The arrangement is such that at each reciprocation of the carriage B the actuating member 134 striking the ratchet finger 132 rotates the ratchet lever 130 and consequently moves the ratchet wheel one tooth. A spring pressed stop pawl 137 is mounted in the hous ing.128 and prevents the rotatlon of the ratchet wheel in the opposite direction. 138 is a dial journaled upon the shaft 129 and provided with graduations upon the outer surface thereof. This dial carries an inward- -ly extending arm 139 in which is slidably end thereof and a cam 142' at the opposite end. The cam is provided with teeth 143 adapted to engage the teeth of the ratchet wheel and is normally held in engagement therewith by the spring 144. The arrangement, is such that by withdrawing the handle 141, the cam may be set in any predetermined position with respect to the ratchet wheel and preferably the position selected is determined by the fixed pointer 145. The graduations upon the dial 138 correspond to the maximum number of teeth which can be ground before the automatic stop takes place.

operative relation to the grinder wheel in its A horizontal shaft 146 is arranged adjacent the housing 128 and has rockably mountthe path of the cam 142 and arranged to be actuated thereby upon a predetermined movement of the ratchet wheel. The tri 147 is keyed or otherwise secured to the sha 146 and' at the outer end of the latter is arranged a handle 150 by which the trip 147 may be manually rocked. A in 151 in the upper portion of the trip 14 is manually ad ustable by means of a transverse pin 152 to engage a' recess 153 in the adjacent trip 148 thereby locking both trips together. The pin 152 is slidable through'the slot 154 and may be held in either position of adjustment by laterally moving the same into the recesses 155 and 156. The trip 147 has the lug 157 projecting therefrom normally held in the path of'th'e carriage clutch release arm 158 by means of a spring pressed plunger 159 with a rock arm 163 to which is .fastenedone end of a link 183, the other end of the link being connected to a rock arm 184, is also connected by a link 186 to an arm 187 of the rockable member 188, the latter carrying also the shifting arm 103 which, in turn, has a roller 189 engaging the clutch collar 102. A spring 164 is secured to the rock arm 184 and anchored to the frame of the machine, this arrangement providing resilient means for urging the clutch out of engagement. For engaging the clutch to start the carriage the handle 161 is rocked clockwise, thereby causing projecting lug 157 to ride over cam lug 162 until it is in front of the sanie, when the pressure of the spring pressed plunger 159 causes the lug 157 to drop in front of the cam 'lug forming a stop to prevent return movement of the release arm and thereby hold the clutch engaged.

The mechanism for stopping both the carriage and the grinding wheel comprises a rod 165 arranged within the tube 160 and secured at its upper end to the release arm 166.

The latter is arranged directly above the carriage release arm 158 and is provided with a cam lug 167 adapted to engage behind the projecting'lug 168 of the trip 148. The lowor end of the rod 165 has a rock arm 169 con-- accomplish t is pur ose, it is necessary to.

lock the trip 148 to t e trip 147 by laterall moving the pin 151 into the recess 153. Bot clutches are now released either by the handle 150 or by the engagement of the cam 142 with cam 149.

The operation-of the automatic stop mechanism as above described, is as follows. The handle 141 is first pulled outwardly to release the cam 142 from the ratchet wheel and the dial 138. is then rotated until the gradubeen ation indicating the number of teeth on the gear to be ground is opposite the pointer 145. The handle 141 is then released thus locking the cam 142 to the ratchet wheel. The machine is then started by operating the handles 176 and 161 and at each reciprocation of the carriage a gear tooth is ground and at the same time the ratchet wheel is advanced one tooth. When the last tooth has ound the cam 142 striking the cam 149 o the trip mechanism releases the trips and disengages the-clutches.

When setting up the grinding machine for a particular gear, it is necessary that the gear be angularly adjusted on the work spin dle C to correspond with the setting of the grinder wheel. In order to provide a rapid means for properly adjusting1 have provided the arbor wit a collar 177 adjustably clamped thereon by suitable means such as the set screw 178. This collar has a slot 179 extending longitudinall thereof in which may be inserted a kni e blade 180. The latter has an arm 181 projecting outwardly therefrom into registration with the gear to be ground. The knife blade 180 is inserted in the slot and the gear D rotated upon the arbor until it contacts with the projecting arm 181, after which, the gear is clamped upon the'arbor by suitable clamping means such as the nut and washer 182. What we claim as our invention is 1. In a gear grinding machine, a reciproextending perpen 'cularly to said face, and

the gear, we

plane face, a wheel spindle-- msans for adjustably mounting said wheel sp ndle on said base, whereby the plane of said faceis inclined alternatively in opposite d1rections corresponding to the pressure angle of said gear.

2. In a gear grindin machine, the combination with a base or rams having a vertically adjustable slide thereon, a ring secured to said slide having teeth thereon, a wheel head rotatably mounted on said slide, a wheel spindle journaled in said wheel head, a grinding wheel on said wheel spindle, a shaft in said wheel head having a pinion thereon meshing with the teeth on said ring, means for rotating said shaft whereby said wheel head is angularly adjusted, and means for clamping said wheel head to said slide.

3 In a-gear grindin machine, the combinatlon with abase, 0 a rotatable grinding wheel journaled thereon, a carriage reciprocable on said base, a wiirk spindle on said carnage, means for oscillating said work spindle'in timed relation to the reciprocation of said carriage, means actuated intermittently at each reciprocation of said carriage, a common driving means for said grinding wheel and said carriage, a clutch controlling both said grinding wheel and carriage, a second clutch controlling only said carriage, means actuated after a predetermined number of reciprocations of said carriage for disengaging one of said clutches, and means cooperating with said first mentioned means to simultaneously disen age said second clutch.

4. In a ear grin 'ng machine, the combination wit a reciprocating carriage, an oscillating spindle thereon adapted to carr the gear to be ground, a grinding wheel a apted to be engaged by said gear during the reciprocation o for said carriage and grinding wheel, a clutch controlling both said carriage and grinding wheel, a second clutch controlling only said carriage, ratchet mechanism operated by each reciprocation of said carriage, a pair of trips normally holding the respective clutches engaged, means for automatically releasing one of said trips after a predetermined movement of said ratchet mechanism, and means for connecting the second trip to said first trip whereby both are simultaneously actuated.

5. In a gear grinding machine, the combination with a grinding wheel, of a work spindle, means for clamping a gear on said spindle, means for oscillating and reciprocating said work spindle to impart a rolling motion to said ear relative'to said grinding'wheel, a rotata ly adjustable collar on said spindle, said collar having an open-sided longitudinal slot therein, a knife gauge havin a pora finger on said knife gauge adapted to contact with'a tooth of said gear.

6. In a gear grinding machine, the comsaid carriage, driving means tion for removably engaging said s 0t, and

bination with a frame and a reciprocable carriage, of a cam drum journaled in said frame, an oscillating lever pivoted to said frame, a transverse pm on said lever engaging said cam drum, a member connecting said lever and said carriage for reciprocatingfhe latter, and means for adjusting said mem er toward and away from the pivot of said lever to vary the stroke of said carriage.

7. In a gear grinding machine, the combination with a frame and a reciprocable carriage, of a cam drum ournaled in said frame, an oscillating lever pivoted to said frame, a transverse pin on said lever engaging said cam drum, a pin projecting upwardly from said lever, a cross member secured to said pin, means for clamping said cross member to said carriage, and means for longitudinally adjusting said carriage when said cross member is unclamped.

8. In a gear grinding machine, the combination with a frame and a reciprocating carriage, of a cam drum j ournaled in said frame, an oscillating lever pivoted to said frame, a transverse pin on said lever engaging said cam drum, said lever having longitudinal guide ways therein, a block sliding in said guide ways, a transversely slotted cross member, a pin extending from said block throu h the slot in said cross member, means or clamping said pin to said cross member,

means for clamping said. cross member to said carriage, and means for longitudinally adjusting said carriage when said cross member is unclamped.

9. In a gear grinding machine, the combination of means for supporting a gear, a rotatable grinding wheel having a face for engaging a tooth surface of said gear, means for angularly adjusting said grinding wheel so that said face is inclined alternatively on opposite sides of a vertical plane an amount corresponding-to the pressure angle of the gear teeth.

10. In a gear grinding machine, the combination of a rotatable grinding wheel having a working face for engaging a gear tooth, a gear-supporting arbor, means for imparting a rolling motion to the gear on said arbor relative to said grinding wheel, means for angularly adjusting said grinding wheel to incline the working face thereof to the pressure angle of the gear alternatively on opposite sides of the center line of the gear, and means for adjusting the relation of said grinding wheel and said gear-supporting arbor in transverse directions, whereby the working face of said grinding wheel is in operative relation alternatively to the opposite sides of the gear teeth.

11. In a gear grinding machine, the combination of a rotatable grinding wheel having a working face transverse to the axis of rotation, a gear-supporting arbor, means for reciprocating and oscillating said arbor to impart a rolling motion to the gear relative to said grinding wheel, means for an ularly adjusting said grinding wheel to inclme the working face thereof to the pressure angle of the gear alternatively on opposite sides of the center line of the gear, means for adjust ingsaid grindingwheel in a direction transverse to the line of rolling of said gear, and means for adjustmg said gear-carrying arbor in the direction of said line of rolling.

12. In a gear grinding machine, the combination of a base, a head swivelled on said base, a rotatable grinding wheel journaled in said head having a working face transverse to the axis of rotation, means for supporting a gear in operative relation to said grinder Wheel, means for imparting a rolling 13. In a gear grinding machine, the com-' bination of a base, a wheel head swivelled on said base, a rotatable grinding wheel journaled in said head having a working face extending transverse to the axis of rotation thereof, a carriage reciprocable on said base in a substantially horizontal plane, a gearcarrying arbor journaled in said carriage, means or reciprocating said carriage and oscillating said arbor to impart a rolling motion to said gear, means for adjusting said wheel head to incline said working face alternatively on opposite sides of a vertical plane, whereby opposite sides of the gear teeth may be ground, means for vertically adjusting said wheel head on said base, and means for horizontally adjusting the normal position of said carriage on said base, said vertical and horizontal adjustments being ada ted to compensate for the displacement 0 said grinding Wheel in its opposite positions of angular adjustment. 7

14-. In a gear grinding machine, the combination with a base, of a head swivelled on said base, an arbor journaled in said head, a grinding wheel having a working face in a plane perpendicular to said arbor, means for mounting said grinding Wheel on said arbor with its working face arranged alternativel on opposite sides, means for angularly a justing said swivelled head to inclme the working face of said grinding wheel alternatively on opposite sides of a vertical plane, a carriage horizontally reciprocable on said base, a gear-carrying arbor rotatable in said carriage and adapted to support a gear above said grinding wheel, means for reciprocating said carriage and oscillating g motion to said work spindle, means for ro- ,t a ting said grinding said arbor to impart a rolling motion to ...wheel head, said ring having teeth formed in a portion thereof, a shaft in said Wheel head having a pinion thereon meshing with the teeth on said ring, and meansfor rotating said pinion to angularly adjust said Wheel head.

16. In a gear grinding machine, the combination with a base, of a rotatable grinding wheel journaled thereon, a carriage reciprocable on said base, a workspindle journaled on said carriage, means for reciprocating said carriage and oscillating said work spindle in timed relation to impart a rolling wheel, meansactuated by a predetermine number of reciprocations of said carriage for automatically stopping'the movement of said carriage, means for-stopping the rotation of said grinding wheel, and manually operable means for connecting said wheel stopping. means to said carriage stopping means whereby the former is automatically operable with the latter.

17. In a gear grinding machine, the combination with a base, of a rotatable grinding wheel journaled thereon, means for rotating said grinding wheel, a carriage reciprocable on said base, a Work spindle journaled on said carriage, means for reciprocating said carriage and oscillating said work spindle in timed relation to impart a rolling motion to the work relative to said grinding wheel, a clutch controlling both the rotation of said grinding wheel and the reciprocation of said carriage, a second clutch controlling said carriage only, means actuated for a predetermined number of reciprocations of said carriage for automatically disengaging the second mentioned clutch, manually operable means for controlling the first mentioned clutch, and means for connecting said manually operable means to said automatically operable means to automatically operate the former with the latter. a

18. In a gear grinding machine, the combination with a frame and a reci rocable carriage, of a cam journaled in sai frame, an oscillatinglever pivoted to said frame, having a cam follower portion engagin said cam, a member connectmgsaid lever an said 19. In a gear grinding machine, the combination of a rotatable grinder wheel having a working face for engaging a gear tooth, a gear-supporting arbor arranged abovesaid grinding wheel and means for an ularly ad- ]usting said grindin wheel to Incline the working face thereo to the pressure angle of'the gear alternatively on opposite sides of the center line of the gear.

20. In a gear grinding machine, the combination of a rotatable grinding wheel having a working face for engaging a gear tooth, a gear-supporting arbor arranged above said grinding wheel, means for imparting a rolling motion to the gear-carrying arbor relative to said grinding wheel, means for an larly adjusting the grinding wheel to incline the worln'ng face thereof to the pressure angle of the gear alternatively on opposite sides of the center line of the gear and means for adjusting the relation of said grinding wheel and said gear-supporting arbor in transverse directions for suflicient distances to enable the working face of said grinding wheel to alternatively engage the opposite sides of the gear teeth.

In testimony whereof we aflix our signa- ALBERT J. OTT.

CONRAD L. OTT.

' tures.

" carriage for reciprocating the latter and means for adjusting said member toward and away from the pivot of said lever to vary the stro e of said carriage. 

